Human Anatomy Part 2 - K. A. Dyubenko, A. K. Kolomiyytsev, Yu. B. Chaykovsky 2008

Special Part
Cardiovascular system, systema cardiovasculare - General Information
Circulatory loops - Lesser (pulmonary) circulation

It originates from the pulmonary trunk, truncus pulmonalis, emerging from the cavity of the right ventricle. The ventricle receives venous Blood flowing from the right atrium through the atrioventricular opening. Upon contraction of the right ventricle, blood is forced into the pulmonary trunk, which bifurcates into the right and left pulmonary Arteries. The pulmonary arteries enter the Lungs through the hilum and branch into arteries, arterioles, precapillaries, and capillaries. Capillaries envelop the pulmonary alveoli, where gas exchange takes place (carbon dioxide passes from the blood into the lungs, while oxygen passes from the lungs into the blood). Venous blood becomes oxygenated, turning back into arterial blood, and flows from the capillaries into venules and Veins, which merge to form two Pulmonary veins emerging from each lung to return to the left atrium.

Thus, arterial blood flows via the four pulmonary veins into the left atrium, marking the end of the Pulmonary Circulation. Subsequently, blood passes through the left atrioventricular opening into the left ventricle, which gives rise to the systemic circulation.



Last update: 08/08/2026

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